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I need help

I have, since 1975, an integrated amplifier by Sansui model AU 7700.

It had what I think were jumpers connected to the right and left entry RCA connectors of Phono 2 that I suppose were, in the absence of the Phono 2, to simulate it.

I also suppose that the jumpers have an specific impedance.
I recently send it to maintenance and the technician lost these jumpers.

If anyone is familiar with this equipment, and what I am calling jumpers, could you please check if I am right about my idea of their function and, if so, which is their  impedance so that I can manufacture a replacement?

Thank you very much for any information.

Fabio

fabio_zaidan
dekay's avatar
dekay
6,180 posts
 

Dill:

Why do you think this?

Are the "jumpers" you mention depicted in the pic the OP posted that I cannot view on DropBox?

If so, why would they be used on unused phono inputs?

"That is all - again."

 

DeKay

dill
2,634 posts
 

The below link goes to a photo of the unit with the metal U plugs installed.

Installed

fabio_zaidan OP
4 posts
 

Dill, the jumpers shown in the photo are not necessary because, as you can see right above the jumpers, the connection  pre-main is made with a switch.

Please, check if you can access the link below. It’s a picture of the rear panel of my amp with the original shorting plugs connected to the Phono 2 input.

fabio_zaidan OP
4 posts
 

https://www.dropbox.com/scl/fi/y3b5ow88y0yn1sl4pdvqw/Capture.JPG?rlkey=tfv2sa95w7iye3mmp9480ii2l&st=waz66buw&dl=0

imhififan's avatar
imhififan
2,257 posts
 

With the picture and the manual in hand, everything is clear now.

In page 2 of the manual, those are the plastic covers.

IMPORTANT PRECAUTIONS

3. Nine pin jack covers are supplied with the set. Be sure to insert these cover into the unused pin jacks on the rear panel to avoid dust accumulation.

And in page 12, those " jumpers connected to the right and left entry RCA connectors of Phono 2 " are indeed the shorting caps (or shorting plugs) that @dekay mentioned in his earlier post. 

SHORT-CIRCUIT PIN PLUGS
When you unpack the set, you’ll find special pin plugs inserted into the PHONO-2 jacks. Their function is to short-circuit the plus and minus terminals of the input circuit and thus prevent any noise from being generated by them when these jacks are not in use. Therefore, if you use the PHONO-2 jacks, re-position these plugs into the PHONO-1 jacks. Or, when both PHONO-1 and PHONO-2 jacks are used, keep them elsewhere for later use. Do NOT insert them into the output jacks (such as TAPE REC), or the sound from the set will be cut off.

https://steampoweredradio.com/pdf/sansui/manuals/au7700%20operating%20instructions.pdf

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